Method for handling sinter



May 13, 1930.

A. J. BOYNTON 1,758,496

IBTKOD FOR HANDLING SINTER 2 ShaetkSheet 1 Filed March 16, 1925 May 13,1930. A. J. BOYNTON 1,758,496

'IETHOD FOR HANDLING SIN'I'ER Q Filed March 16, 1925 2 Sheets-Sheet 2irzoarzzbr' 545 LPQrflzar Jliqy t 9: l J y I Patented May 13, "1930UNITED STATES PATENT OFFICE El-ml. BOYIN'TON, OF'CHICAGO, ILLINOIS,ASSIGNOB TO H. A. BRASSERT, INQ, OF

' CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS METHOD FOR HANDLINGSIHTER Application filed March 16, 1925. Serial No. 15,962.

This invention relates to a new and improved method for handlingmaterial and more particularly, to a. method adapted to screen and coolthe product of a sintering process.

The invention has particular application to the handling of sinter madeby processes well known in the art, the sintering having for its objectthe agglomerating of metalliferous ores and flue dust in its fine stateof division. In somesintering processes themethod alsoserves toeliminate from the ores by combustion,

sulphur or other combustible substances. Usually the primary object ofthe sintering process is to increase in size the pieces of ore which aresubsequently used in the charge of a metallurgical furnace.

In one sintering process as now carried out the metallic charge,generally in a fine state of division, is spread upon the grate bars ofa so-called sintering pan mixed with a definite percentage of fuel. Thisfuel may be contained in the charge as a resultof previous introductioninto a furnace, as in the caseof blast furnace. Flue dust, or the fuelmay be added for the pur ose of sintering. After the'spreading of thecharge, the fuel is ig nited and combustion is maintained by means of acurrent of air drawn down through the char e from the upper surfacethrough interstices in the grate bars which support the charge, by asuction draft. At the conclusion of the process, the resulting sinter isan agglomerated mass in a more or less plastic state.

The pan is then inverted so that the sintered material falls on aninclined surface below the pan, part of which surface is usuallyprovided with a screen or bars for the purpose of removing from theproduct any portion of the sinter which is in too fine a state ofdivision to adapt it for use. The remainder of the sinter passes down aninclined surface without retardation into a freight car or other recetacle. This dumping of the sinter on the inclined surface and thesubsequent motion of the sinter over screens and into the car has thedisadvantage of severe breakage. and abrasion of the plastic sinter,which reduces it in size and thus in part defeats the object of thesintering process. Also, the car or other receptacle is subject todamage by the residual heat in the sinter.

A further objection to this method lies in the fact that the screeningwhich is ossible to effect by rapid motion over a steep y inclinedscreen is not suitable "for the objects of the sintering process sincethe rapid motion of the sintered products prevents the elimination offines, except on a basis of screening so coarse that much sinteredproduct suitable for use is allowed to pass through the screen with thefines. Also, this practice provides no means for reducing pieces ofsinter which are objectionably large.

It is an object of the present invention to rovide a new and improvedmethod for iandhng sinter whereb the sinter may be air cooled, crushedto re uce large pieces and screened at a slow rate of speed whereby theproduction of fines is reduced and the elimination" of fines moreefficiently effected.

It is a further ob'ect of the invention to provide a method 0 thischaracter whereby the sintered mass is air cooled before being crushed,or screened, whereby its hardness is increased and the product-ion offines reduced.

It is an additional object to provide a method of this character whichis simple and adapted for commercial application to existin sinteringapparatus.

t is also an ob'ect to provide a new and improved metho of handlingsinter by which the sinter is air cooled before crushin crushed andscreened, the fines produced being reduced in quantity by the coolingpreliminary to the crushing.

Other and further objects will appear as the description proceeds.

I have illustrated a preferred form of apparatus somewhatdiagrammatically in the accompanying drawings, in which- Figure 1 isaside elevation, and

Figure 2 is a front elevation of the apparatus.

Referring to the drawings,-

The sintering pan 11 is supported on trunnions 12 about which it may berotated to dump the sinter into the hopper 13. The

lateral walls of this hop er are ai f ht and its bottom is formed rom ap ur a lity of downwardly inclined overlapping plates 14, which areseparated suificiently to permit the passage of air into the hopper butto prevent discharge of the sintered product. The passage 15 extendsfrom the upper end of the hopper and leads to any source of draft, suchas a stack.

The lower end of the hopper 13 is closed by the gate 16 operated bylever 17. The feed roller 18, which is diyided into a plurality ofcompartments 19, is located below the gate 16. Below the feed roller'l8are located the pair of crusher rolls 20 and 21. These rolls dischargeonto the screen 22, which has been shown in the form of a bar screen orgrizzly. Below the screen 22 is located a opper 23 having thebottom 24similar in construction to the bottom 14 of the hopper 13. The dischargeand of the hopper 23 is controlled by gate Below gate 25 is located thescreen 26, which may be vibrated electricallyor mechanically by anyknown process. Material passing over the screen 26 is discharged throu hchute 27 intocajr 28. Material passing t rough the screen 26 isdischarged through spout 29 into receptacle 30. Material passing overthe bar screen 22 passes down the upper surface 31 of the chute 27 intothe car 28.

In the operation of the apparatus, the sintered material is dumped fromthe sintering pan into the hopper 13 and the heat of the materialinduces a draft through the bottom 14 and up the stack 15. This flow ofair is distributed through the material by the nature of the bottom andserves to cool and harden the sinter. The gate' 16 is opened todischarge the material as desired and the flow is further controlled bythe feed roller 18, which ma be rotated at any desired speed suitablefor t e purpose. The material pass- 'ing through the rollers 20 and 21has the lar er pieces reduced to a suitable size.

he material passing over the bar screen 22 has the larger ieces feddirectl to the car 28. The sma ler pieces and the fines which are toosmall for usepass through the screen 22 and are further cooled by aircoming through the bottom24. This material is passed over the screen 26at a rate of flow controlled by the gate 25. As has been stated, thescreen 26 may be vibrated to give a more eflicient screening action. Thescreen 26 eliminates the fines and the remaining material is dischargedto the car. 1

This apparatus serves to cool the material thus hardening it andminimiz' the breakage of the material into finea he cooling also servesto revent damage to the car or other receptac e. The crusher rollsprevent the passa e of material in larger pieces than is desirab e. Thegates and feed roll control the rate of passage of material, so that itmay be caused to pass over the screens slowly in a thin layer. hescreens may therefore, be of a proper size to eliminate only theundesirable fines and all of the usable material will be passed to thecar.

It is to be understood'that the showing of the drawings is somewhatdiagrammatic, and I contemplate such changes and modifications as comewithin the spirit and scope of the accompanying claims.

I claim:

1. The method of handling sinter which comprises air cooling thematerial and passing it at a controlled rate of flow over screens toremove the fines.

2. The method of handling sinter which comprises air cooling thematerial, crushing it to reduce the larger pieces and passing it at acontrolled rate of flow over screens to remove the fines.

' 3. The method of handling sinter which comprises air cooling thematerial, crushing it to reduce the larger pieces, passing the[ll-lterial over a coarse screen to remove the larger remaining pieces,and passing the material which passes through the first screen over asecond screen to remove the fines.

4. The method of handling sinter which comprises air cooling thematerial, crushing it to reduce the larger pieces, passing the materialover a coarse screen to remove the larger remaining pieces, and againair cooling,,the material which passes through the first screen over asecond screen to remove the fines.

Signed at Chicago, Illinois, this 5th day of February, 1925.

ARTHUR J. BOYNTON.

